//https://leetcode.cn/problems/binary-tree-pruning/

class Solution {
public:
    TreeNode* pruneTree(TreeNode* root)
    {

        if (root == nullptr) return nullptr;

        root->left = pruneTree(root->left);
        root->right = pruneTree(root->right);

        if (root->left == nullptr && root->right == nullptr && root->val == 0)
        {
            //delete root;
            root = nullptr;
        }

        return root;

    }
};